27 Mar
2009
27 Mar
'09
10 a.m.
Martin,
The 1% and 5% don't exactly refer to geography. They refer to the
sampling fraction; the proportion of the total resondents who are
included in the PUMS files.
PUMS geography is based on PUMAs (Public Use Microdata Sample areas)
for the 5% files; these have to be at least 100,000 population. The
1% file uses super-PUMAs, which have to be at least 250,000 in
population size. Your state data center should be able to tell you
what the PUMAs are for your state or area; they're also included in
the 2000 census PUMS documentation.
Hope this helps.
Patty Becker
At 03:37 PM 3/25/2009, you wrote:
Hello,
I am looking to create some commute flow maps and I think I remember
someone mentioning (between all the please remove me from this list
e-mails) that flow maps can be created by using ACS data and the PUMS
geography. I was at the Census site trying to download the PUMS
geography files and found that there were two types 1% and 5%. Does
anyone know which geography file I should use? The 1% or the 5%?
Thanks in advance,
Martin Catala
GIS Manager
CUTR
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Patricia C. (Patty) Becker 248/354-6520
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